Numerous strides have been made in recent years in the field of high speed material processing, including the development of apparatus and processes for providing high speed centrifugal finishing. One such device is disclosed in U.S. Pat. No. 5,355,638 which is incorporated herein by reference in its entirety. The centrifugal finisher disclosed in U.S. Pat. No. 5,355,638 has an outer vessel that is rotatable, and at least one inner vessel located within the outer vessel and which is revolved around the inside surface of the outer vessel while concomitantly rotating about its own axis. A traction surface exists between the inside surface of the outer vessel and the outside surface of the inner vessel. The traction surface allows the outer vessel to restrain the inner vessel while the inner vessel experiences centrifugal forces.
The rotational movement of the inner vessel that is generated in this machine simultaneously transfers momentum from the outer vessel to the inner vessel since the outer vessel is rotated at a different speed and potentially a different direction than the rotational movement of the inner vessel. The resulting motion on the inner vessel is transferred to articles and finishing media contained within the inner vessel, providing high speed polishing of the articles.
An improved device is disclosed in U.S. Pat. No. 5,848,929 which is incorporated herein by reference in its entirety. The apparatus disclosed in U.S. Pat. No. 5,848,929 includes a fixed outer vessel, an inner vessel for containing the item to be finished, and one or more intermediate rollers. A drive system rotates the inner vessels and/or the intermediate rollers around the central axis of the outer vessel. The contact between inner vessel and the intermediate rollers causes the inner vessel to also rotate about its own axis, thereby subjecting the contents of the inner vessel to both centrifugal and rotation motion.
The speeds at which these prior art devices operate are extremely high. In particular, the device shown in U.S. Pat. No. 5,848,929 is currently in operation and has attained speeds which subject the objects being finished to accelerations in excess of 120 g's. These high speeds are very beneficial in a finishing process since they permit the finishing media used to perform efficient finishing of the surface area.
The inventor of the present invention has determined that the high speeds provided by the finishing apparatus discussed above could also be beneficial in other material processing operations. In particular, it has been determined that current welding operations can be improved with the use of high speed centrifugal processing. For example, the high forces generated by a centrifugal apparatus can be combined with a vacuum environment to produce welding of materials. One example is the mixing of cobalt malt with tungsten carbide which is used to make inserts for tools. Currently, this combination can only be achieved when subjected to high temperatures and high pressure. The machinery necessary to produce sufficiently high temperatures and pressure are extremely expensive and the process is relatively time consuming.
A need exists for an improved apparatus and process for providing high speed welding.